Noninvasive evaluation of cerebrospinal fluid pressure in ocular hypertension: a preliminary study

Purpose To compare the orbital cerebral spinal fluid pressure ( CSFP ) and trans‐lamina cribrosa pressure difference ( TLCPD ) determined noninvasively in ocular hypertensive ( OH ) subjects and controls. Methods Cross‐sectional observational study. Magnetic resonance imaging was used to measure orbital subarachnoid space width ( OSASW ). The CSFP (mm Hg) was estimated from a published formula as 17.54 ×  MRI derived OSASW at 15 mm behind the globe + 0.47 × body mass index + 0.13 × mean arterial blood pressure −21.52. Estimated TLCPD was calculated as IOP ‐ CSFP . Results The orbital subarachnoid space width was significantly wider (p   =   0.01) in the OH group than in the control group at all three measurement locations. The MRI derived CSFP value in OH (14.9 ± 2.9 mm Hg) was significantly higher than in the normal group (12.0 ± 2.8 mm Hg; p   <   0.01). The estimated TLCPD value in OH (9.0 ± 4.2 mm Hg) was significantly higher than in controls (3.6 ± 3.0 mm Hg; p   <   0.01). Conclusion The wider OSASW and higher estimated CSFP in OH subjects suggest a higher orbital CSFP . Despite a higher orbital CSFP that could be protective, the higher TLCPD in OH may play a significant role in the risk of developing glaucoma.